Ground Failure Investigation over Abandoned Coal Mines: A Case Study

The slurry backfill operation for the Rock Springs subsidence control project is briefly described. The extent of ground failure and building damage is presented. The scope of the ensuing geotechnical investigation to indicate any possible cause and effect relationship between the pumped slurry backfill operation and observed damage is described. The general and specific findings regarding the damaged area are discussed. Conclusions from the investigation are presented

A Novel Holonomic Mobile Manipulator Robot For Construction Sites

This article describes a novel mobile manipulator robot designed to work at height on construction sites. The robot comprises a mobile platform and a scissor lifter on which an ABB 6 dof manipulator is mounted. The mobile base is characterised by holonomic kinematics, provided by a novel designed omnidirectional wheel system that can travel directly and autonomously to desired poses. The robot was successfully tested in a construction site scenario to perform drilling tasks

Credit and business cycles’ relationship : evidence from Spain

This study provides evidence on the interaction between business and credit cycles in Spain during the period 1970–2014. The paper works on three analyses: the cycle turning points are identified; the main features of credit and business cycles are documented; and in both cycles the causal relationship is assessed. We find differences in the features of the business and credit cycle phases, which lead to a scant degree of synchronization over time. The lack of synchronization might be a sign that the cyclic interaction could be non-contemporaneous. Our results reveal that there is causation. A significant lagged rela- tionship between business and credit cycles is found; specifically, fluctuations of the business cycle lead fluctuations of the credit to non-financial corporations and a lag exists with respect to the fluctuations of the credit to households. We also examine episodes of credit boom and credit crunch. In the period 1970–2014, Spanish credit booms did not involve deeper business cycle contractions and credit crunches were not associated with deeper and longer business cycle contractions. These differences are related with the great importance of the real estate sector in Spain.info:eu-repo/semantics/publishedVersio

A Search for Technosignatures Around 11,680 Stars with the Green Bank Telescope at 1.15-1.73 GHz

We conducted a search for narrowband radio signals over four observing sessions in 2020-2023 with the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope. We pointed the telescope in the directions of 62 TESS Objects of Interest, capturing radio emissions from a total of ~11,680 stars and planetary systems in the ~9 arcminute beam of the telescope. All detections were either automatically rejected or visually inspected and confirmed to be of anthropogenic nature. In this work, we also quantified the end-to-end efficiency of radio SETI pipelines with a signal injection and recovery analysis. The UCLA SETI pipeline recovers 94.0% of the injected signals over the usable frequency range of the receiver and 98.7% of the injections when regions of dense RFI are excluded. In another pipeline that uses incoherent sums of 51 consecutive spectra, the recovery rate is ~15 times smaller at ~6%. The pipeline efficiency affects calculations of transmitter prevalence and SETI search volume. Accordingly, we developed an improved Drake Figure of Merit and a formalism to place upper limits on transmitter prevalence that take the pipeline efficiency and transmitter duty cycle into account. Based on our observations, we can state at the 95% confidence level that fewer than 6.6% of stars within 100 pc host a transmitter that is detectable in our search (EIRP > 1e13 W). For stars within 20,000 ly, the fraction of stars with detectable transmitters (EIRP > 5e16 W) is at most 3e-4. Finally, we showed that the UCLA SETI pipeline natively detects the signals detected with AI techniques by Ma et al. (2023).Comment: 22 pages, 9 figures, submitted to AJ, revise

Friction Gages for In-Situ Rock- Mass Deformability and Stress Measurements

Introduction In-situ deformability of rock and the state-of-stress must be known for the precise analysis and design of structures in or on rocks. The in-situ mechanical properties and the state-ofstress are needed in order to predict rock response to changed loading conditions caused by construction or excavation. Included in construction and excavation are both traditional activities and new engineering procedures such as in-situ extraction of geothermal power, in-situ coal gasification, and storage of high-level radioactive waste. Laboratory testing yields inaccurate estimates of true properties, since rock core samples do not represent the rock-mass adequately. Thus, a number of field methods and techniques have been developed for rock-mass behavior and state-of-stress determination (Schrauf and Pratt, 1979). Large-scale testing techniques provide the best estimates. These methods reflect the behavior of larger, more representative volumes of rock-mass. However, large-scale testing techniques require bulky equipment and extensive site preparations; they are usually expensive, time consuming, and limited to shallow depths. Furthermore, the rock-mass specimens are significantly disturbed, and their boundaries are modified, introducing bias to the estimate. Borehole testing methods and geophysical techniques are, in general, more economical, rapid and suitable for deep measurements. Furthermore, the rock-mass specimens remai